The present invention relates to a wafer inspection device that performs electrical inspection of a wafer on which a plurality of semiconductor integrated circuit devices are formed and a semiconductor wafer inspection method using the same. In particular, the present invention relates to a wafer inspection device that performs electrical inspection by pressing a probe card for inspection against a wafer and a semiconductor wafer inspection method using the same.
During manufacturing of a semiconductor integrated circuit, a plurality of semiconductor integrated devices (chips) are simultaneously formed through a diffusion process performed to a semiconductor wafer. However, in the manufacturing process, all the plurality of chips simultaneously manufactured are usually difficult to be made non-defective articles due to various factors, such as dust. Therefore, the plurality of chips simultaneously manufactured on a wafer need to be individually inspected in a wafer level whether or not each chip is non-defective before the chips are separated and assembled. For the inspection, a probe card having a contact terminal to be electrically connected to one or a plurality of chips on a wafer and an inspection device, referred to as a prober, that conveys the wafer, aligns the same with the probe card, and then presses the wafer against the probe card are used (Japanese Patent Publication No. 2003-59986).
In recent years, due to an improvement of a device for performing electrical inspection, referred to as a tester, that generates a power supply or electrical signals, transmits the power supply and the signals to a wafer, and processes the signals returned from the wafer, a larger number of semiconductor chips can be inspected at once and a probe card for collectively and simultaneously inspecting wafers has also been increasingly supplied.
However, with an increase in the number of chips to be simultaneously inspected, a higher force for pressing a wafer against a probe card is required. The pressing force is obtained by rotating a ball screw by a stepping motor or the like, and there is a limitation in the force with a single mechanism. In usual, 2 to 4 stepping motors are provided, but there is a limitation in increasing the number of the stepping motors also in terms of an area for providing the same. The probe card to be pressed is required to maintain the degree of flatness with a reinforcing plate in such a manner as not to be curved by the pressing force (e.g., Nicolas Salles, Wayne Nelson, “Reinforcement of PCB using Advanced Stiffeners for High Pin Count Devices” IEEE Semiconductor Wafer Test Workshop 2007, Session 4-2, June, 2007, Internet <URL:http://www.swtest.org/swtw_library/2007 proc/PDF/S04—02_Salles_SWTW2007.pdf>. Moreover, with an increase in the number of chips to be simultaneously inspected, the area of the contact terminal of a probe card inevitably increases, and thus the degree of parallelism of the probe card and the wafer is also important. When the degree of parallelism thereof fluctuates, so-called uneven contact makes it difficult to achieve uniform contact on the entire surface (e.g., Sunil Wijeyesekera, Makarand Shinde, “One Touch 300 mm Wafer Probing” IEEE Semiconductor Wafer Test Workshop 2006, Session 5-2, June, 2006, Internet <URL:http://www.swtest.org/swtw_library/2006 proc/PDF/S05—01_Wijeyesekera.pdf>. As a method for solving the problem, a method for obtaining a load value by a differential pressure with the atmospheric pressure using a wafer tray is disclosed in Japanese Patent Publication No. 08-5666.